usb: chipidea: add support for roles

Add some generic code for roles and implement simple role switching
based on ID pin state and/or a sysfs file. At this, we also rename
the device to ci_hdrc, which is what it is.

The "manual" switch is made into a sysfs file and not debugfs, because
it might be useful even in non-debug context. For some boards, like
sheevaplug, it seems to be the only way to switch roles without modifying
the hardware, since the ID pin is always grounded.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/bits.h

@@ -50,6 +50,24 @@
 #define DEVLC_PSPD            (0x03UL << 25)
 #define    DEVLC_PSPD_HS      (0x02UL << 25)
 
+/* OTGSC */
+#define OTGSC_IDPU	      BIT(5)
+#define OTGSC_ID	      BIT(8)
+#define OTGSC_AVV	      BIT(9)
+#define OTGSC_ASV	      BIT(10)
+#define OTGSC_BSV	      BIT(11)
+#define OTGSC_BSE	      BIT(12)
+#define OTGSC_IDIS	      BIT(16)
+#define OTGSC_AVVIS	      BIT(17)
+#define OTGSC_ASVIS	      BIT(18)
+#define OTGSC_BSVIS	      BIT(19)
+#define OTGSC_BSEIS	      BIT(20)
+#define OTGSC_IDIE	      BIT(24)
+#define OTGSC_AVVIE	      BIT(25)
+#define OTGSC_ASVIE	      BIT(26)
+#define OTGSC_BSVIE	      BIT(27)
+#define OTGSC_BSEIE	      BIT(28)
+
 /* USBMODE */
 #define USBMODE_CM            (0x03UL <<  0)
 #define    USBMODE_CM_IDLE    (0x00UL <<  0)

drivers/usb/chipidea/ci.h

@@ -14,6 +14,7 @@
 #define __DRIVERS_USB_CHIPIDEA_CI_H
 
 #include <linux/list.h>
+#include <linux/irqreturn.h>
 #include <linux/usb/gadget.h>
 
 /******************************************************************************
@@ -47,6 +48,26 @@ struct ci13xxx_ep {
 	struct dma_pool                       *td_pool;
 };
 
+enum ci_role {
+	CI_ROLE_HOST = 0,
+	CI_ROLE_GADGET,
+	CI_ROLE_END,
+};
+
+/**
+ * struct ci_role_driver - host/gadget role driver
+ * start: start this role
+ * stop: stop this role
+ * irq: irq handler for this role
+ * name: role name string (host/gadget)
+ */
+struct ci_role_driver {
+	int		(*start)(struct ci13xxx *);
+	void		(*stop)(struct ci13xxx *);
+	irqreturn_t	(*irq)(struct ci13xxx *);
+	const char	*name;
+};
+
 struct hw_bank {
 	unsigned      lpm;    /* is LPM? */
 	void __iomem *abs;    /* bus map offset */
@@ -85,8 +106,47 @@ struct ci13xxx {
 	struct ci13xxx_udc_driver *udc_driver; /* device controller driver */
 	int                        vbus_active; /* is VBUS active */
 	struct usb_phy            *transceiver; /* Transceiver struct */
+	struct ci_role_driver     *roles[CI_ROLE_END];
+	enum ci_role               role;
+	bool			   is_otg;
+	struct work_struct	   work;
+	struct workqueue_struct	  *wq;
 };
 
+static inline struct ci_role_driver *ci_role(struct ci13xxx *ci)
+{
+	BUG_ON(ci->role >= CI_ROLE_END || !ci->roles[ci->role]);
+	return ci->roles[ci->role];
+}
+
+static inline int ci_role_start(struct ci13xxx *ci, enum ci_role role)
+{
+	int ret;
+
+	if (role >= CI_ROLE_END)
+		return -EINVAL;
+
+	if (!ci->roles[role])
+		return -ENXIO;
+
+	ret = ci->roles[role]->start(ci);
+	if (!ret)
+		ci->role = role;
+	return ret;
+}
+
+static inline void ci_role_stop(struct ci13xxx *ci)
+{
+	enum ci_role role = ci->role;
+
+	if (role == CI_ROLE_END)
+		return;
+
+	ci->role = CI_ROLE_END;
+
+	ci->roles[role]->stop(ci);
+}
+
 /******************************************************************************
  * REGISTERS
  *****************************************************************************/
@@ -107,6 +167,7 @@ enum ci13xxx_regs {
 	OP_ENDPTLISTADDR,
 	OP_PORTSC,
 	OP_DEVLC,
+	OP_OTGSC,
 	OP_USBMODE,
 	OP_ENDPTSETUPSTAT,
 	OP_ENDPTPRIME,
@@ -118,7 +179,6 @@ enum ci13xxx_regs {
 	OP_LAST = OP_ENDPTCTRL + ENDPT_MAX / 2,
 };
 
-
 /**
  * ffs_nr: find first (least significant) bit set
  * @x: the word to search
@@ -193,8 +253,6 @@ static inline u32 hw_test_and_write(struct ci13xxx *udc, enum ci13xxx_regs reg,
 	return (val & mask) >> ffs_nr(mask);
 }
 
-int hw_device_init(struct ci13xxx *udc, void __iomem *base,
-		   uintptr_t cap_offset);
 int hw_device_reset(struct ci13xxx *ci);
 
 int hw_port_test_set(struct ci13xxx *ci, u8 mode);

drivers/usb/chipidea/ci13xxx_msm.c

@@ -62,9 +62,9 @@ static int ci13xxx_msm_probe(struct platform_device *pdev)
 
 	dev_dbg(&pdev->dev, "ci13xxx_msm_probe\n");
 
-	plat_ci = platform_device_alloc("ci_udc", -1);
+	plat_ci = platform_device_alloc("ci_hdrc", -1);
 	if (!plat_ci) {
-		dev_err(&pdev->dev, "can't allocate ci_udc platform device\n");
+		dev_err(&pdev->dev, "can't allocate ci_hdrc platform device\n");
 		return -ENOMEM;
 	}
 

drivers/usb/chipidea/ci13xxx_pci.c

@@ -69,9 +69,9 @@ static int __devinit ci13xxx_pci_probe(struct pci_dev *pdev,
 	pci_set_master(pdev);
 	pci_try_set_mwi(pdev);
 
-	plat_ci = platform_device_alloc("ci_udc", -1);
+	plat_ci = platform_device_alloc("ci_hdrc", -1);
 	if (!plat_ci) {
-		dev_err(&pdev->dev, "can't allocate ci_udc platform device\n");
+		dev_err(&pdev->dev, "can't allocate ci_hdrc platform device\n");
 		retval = -ENOMEM;
 		goto disable_device;
 	}

drivers/usb/chipidea/core.c

@@ -75,7 +75,7 @@
 /* MSM specific */
 #define ABS_AHBBURST        (0x0090UL)
 #define ABS_AHBMODE         (0x0098UL)
-/* UDC register map */
+/* Controller register map */
 static uintptr_t ci_regs_nolpm[] = {
 	[CAP_CAPLENGTH]		= 0x000UL,
 	[CAP_HCCPARAMS]		= 0x008UL,
@@ -88,6 +88,7 @@ static uintptr_t ci_regs_nolpm[] = {
 	[OP_ENDPTLISTADDR]	= 0x018UL,
 	[OP_PORTSC]		= 0x044UL,
 	[OP_DEVLC]		= 0x084UL,
+	[OP_OTGSC]		= 0x064UL,
 	[OP_USBMODE]		= 0x068UL,
 	[OP_ENDPTSETUPSTAT]	= 0x06CUL,
 	[OP_ENDPTPRIME]		= 0x070UL,
@@ -109,6 +110,7 @@ static uintptr_t ci_regs_lpm[] = {
 	[OP_ENDPTLISTADDR]	= 0x018UL,
 	[OP_PORTSC]		= 0x044UL,
 	[OP_DEVLC]		= 0x084UL,
+	[OP_OTGSC]		= 0x0C4UL,
 	[OP_USBMODE]		= 0x0C8UL,
 	[OP_ENDPTSETUPSTAT]	= 0x0D8UL,
 	[OP_ENDPTPRIME]		= 0x0DCUL,
@@ -118,24 +120,24 @@ static uintptr_t ci_regs_lpm[] = {
 	[OP_ENDPTCTRL]		= 0x0ECUL,
 };
 
-static int hw_alloc_regmap(struct ci13xxx *udc, bool is_lpm)
+static int hw_alloc_regmap(struct ci13xxx *ci, bool is_lpm)
 {
 	int i;
 
-	kfree(udc->hw_bank.regmap);
+	kfree(ci->hw_bank.regmap);
 
-	udc->hw_bank.regmap = kzalloc((OP_LAST + 1) * sizeof(void *),
-				      GFP_KERNEL);
-	if (!udc->hw_bank.regmap)
+	ci->hw_bank.regmap = kzalloc((OP_LAST + 1) * sizeof(void *),
+				     GFP_KERNEL);
+	if (!ci->hw_bank.regmap)
 		return -ENOMEM;
 
 	for (i = 0; i < OP_ENDPTCTRL; i++)
-		udc->hw_bank.regmap[i] =
-			(i <= CAP_LAST ? udc->hw_bank.cap : udc->hw_bank.op) +
+		ci->hw_bank.regmap[i] =
+			(i <= CAP_LAST ? ci->hw_bank.cap : ci->hw_bank.op) +
 			(is_lpm ? ci_regs_lpm[i] : ci_regs_nolpm[i]);
 
 	for (; i <= OP_LAST; i++)
-		udc->hw_bank.regmap[i] = udc->hw_bank.op +
+		ci->hw_bank.regmap[i] = ci->hw_bank.op +
 			4 * (i - OP_ENDPTCTRL) +
 			(is_lpm
 			 ? ci_regs_lpm[OP_ENDPTCTRL]
@@ -171,36 +173,35 @@ u8 hw_port_test_get(struct ci13xxx *ci)
 	return hw_read(ci, OP_PORTSC, PORTSC_PTC) >> ffs_nr(PORTSC_PTC);
 }
 
-int hw_device_init(struct ci13xxx *udc, void __iomem *base,
-		   uintptr_t cap_offset)
+static int hw_device_init(struct ci13xxx *ci, void __iomem *base)
 {
 	u32 reg;
 
 	/* bank is a module variable */
-	udc->hw_bank.abs = base;
+	ci->hw_bank.abs = base;
 
-	udc->hw_bank.cap = udc->hw_bank.abs;
-	udc->hw_bank.cap += cap_offset;
-	udc->hw_bank.op = udc->hw_bank.cap + ioread8(udc->hw_bank.cap);
+	ci->hw_bank.cap = ci->hw_bank.abs;
+	ci->hw_bank.cap += ci->udc_driver->capoffset;
+	ci->hw_bank.op = ci->hw_bank.cap + ioread8(ci->hw_bank.cap);
 
-	hw_alloc_regmap(udc, false);
-	reg = hw_read(udc, CAP_HCCPARAMS, HCCPARAMS_LEN) >>
+	hw_alloc_regmap(ci, false);
+	reg = hw_read(ci, CAP_HCCPARAMS, HCCPARAMS_LEN) >>
 		ffs_nr(HCCPARAMS_LEN);
-	udc->hw_bank.lpm  = reg;
-	hw_alloc_regmap(udc, !!reg);
-	udc->hw_bank.size = udc->hw_bank.op - udc->hw_bank.abs;
-	udc->hw_bank.size += OP_LAST;
-	udc->hw_bank.size /= sizeof(u32);
+	ci->hw_bank.lpm  = reg;
+	hw_alloc_regmap(ci, !!reg);
+	ci->hw_bank.size = ci->hw_bank.op - ci->hw_bank.abs;
+	ci->hw_bank.size += OP_LAST;
+	ci->hw_bank.size /= sizeof(u32);
 
-	reg = hw_read(udc, CAP_DCCPARAMS, DCCPARAMS_DEN) >>
+	reg = hw_read(ci, CAP_DCCPARAMS, DCCPARAMS_DEN) >>
 		ffs_nr(DCCPARAMS_DEN);
-	udc->hw_ep_max = reg * 2;   /* cache hw ENDPT_MAX */
+	ci->hw_ep_max = reg * 2;   /* cache hw ENDPT_MAX */
 
-	if (udc->hw_ep_max == 0 || udc->hw_ep_max > ENDPT_MAX)
+	if (ci->hw_ep_max == 0 || ci->hw_ep_max > ENDPT_MAX)
 		return -ENODEV;
 
-	dev_dbg(udc->dev, "ChipIdea UDC found, lpm: %d; cap: %p op: %p\n",
-		udc->hw_bank.lpm, udc->hw_bank.cap, udc->hw_bank.op);
+	dev_dbg(ci->dev, "ChipIdea HDRC found, lpm: %d; cap: %p op: %p\n",
+		ci->hw_bank.lpm, ci->hw_bank.cap, ci->hw_bank.op);
 
 	/* setup lock mode ? */
 
@@ -250,16 +251,98 @@ int hw_device_reset(struct ci13xxx *ci)
 	return 0;
 }
 
-static int __devinit ci_udc_probe(struct platform_device *pdev)
+/**
+ * ci_otg_role - pick role based on ID pin state
+ * @ci: the controller
+ */
+static enum ci_role ci_otg_role(struct ci13xxx *ci)
+{
+	u32 sts = hw_read(ci, OP_OTGSC, ~0);
+	enum ci_role role = sts & OTGSC_ID
+		? CI_ROLE_GADGET
+		: CI_ROLE_HOST;
+
+	return role;
+}
+
+/**
+ * ci_role_work - perform role changing based on ID pin
+ * @work: work struct
+ */
+static void ci_role_work(struct work_struct *work)
+{
+	struct ci13xxx *ci = container_of(work, struct ci13xxx, work);
+	enum ci_role role = ci_otg_role(ci);
+
+	hw_write(ci, OP_OTGSC, OTGSC_IDIS, OTGSC_IDIS);
+
+	if (role != ci->role) {
+		dev_dbg(ci->dev, "switching from %s to %s\n",
+			ci_role(ci)->name, ci->roles[role]->name);
+
+		ci_role_stop(ci);
+		ci_role_start(ci, role);
+	}
+}
+
+static ssize_t show_role(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct ci13xxx *ci = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", ci_role(ci)->name);
+}
+
+static ssize_t store_role(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	struct ci13xxx *ci = dev_get_drvdata(dev);
+	enum ci_role role;
+	int ret;
+
+	for (role = CI_ROLE_HOST; role < CI_ROLE_END; role++)
+		if (ci->roles[role] && !strcmp(buf, ci->roles[role]->name))
+			break;
+
+	if (role == CI_ROLE_END || role == ci->role)
+		return -EINVAL;
+
+	ci_role_stop(ci);
+	ret = ci_role_start(ci, role);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR(role, S_IRUSR | S_IWUSR, show_role, store_role);
+
+static irqreturn_t ci_irq(int irq, void *data)
+{
+	struct ci13xxx *ci = data;
+	irqreturn_t ret = IRQ_NONE;
+
+	if (ci->is_otg) {
+		u32 sts = hw_read(ci, OP_OTGSC, ~0);
+
+		if (sts & OTGSC_IDIS) {
+			queue_work(ci->wq, &ci->work);
+			ret = IRQ_HANDLED;
+		}
+	}
+
+	return ci->role == CI_ROLE_END ? ret : ci_role(ci)->irq(ci);
+}
+
+static int __devinit ci_hdrc_probe(struct platform_device *pdev)
 {
 	struct device	*dev = &pdev->dev;
-	struct ci13xxx_udc_driver *driver = dev->platform_data;
-	struct ci13xxx	*udc;
+	struct ci13xxx	*ci;
 	struct resource	*res;
 	void __iomem	*base;
 	int		ret;
 
-	if (!driver) {
+	if (!dev->platform_data) {
 		dev_err(dev, "platform data missing\n");
 		return -ENODEV;
 	}
@@ -276,49 +359,112 @@ static int __devinit ci_udc_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
-	ret = udc_probe(driver, dev, base, &udc);
-	if (ret)
-		return ret;
+	ci = devm_kzalloc(dev, sizeof(*ci), GFP_KERNEL);
+	if (!ci) {
+		dev_err(dev, "can't allocate device\n");
+		return -ENOMEM;
+	}
+
+	ci->dev = dev;
+	ci->udc_driver = dev->platform_data;
+
+	ret = hw_device_init(ci, base);
+	if (ret < 0) {
+		dev_err(dev, "can't initialize hardware\n");
+		return -ENODEV;
+	}
 
-	udc->irq = platform_get_irq(pdev, 0);
-	if (udc->irq < 0) {
+	ci->irq = platform_get_irq(pdev, 0);
+	if (ci->irq < 0) {
 		dev_err(dev, "missing IRQ\n");
+		return -ENODEV;
+	}
+
+	INIT_WORK(&ci->work, ci_role_work);
+	ci->wq = create_singlethread_workqueue("ci_otg");
+	if (!ci->wq) {
+		dev_err(dev, "can't create workqueue\n");
+		return -ENODEV;
+	}
+
+	/* initialize role(s) before the interrupt is requested */
+	ret = ci_hdrc_gadget_init(ci);
+	if (ret)
+		dev_info(dev, "doesn't support gadget\n");
+
+	if (!ci->roles[CI_ROLE_HOST] && !ci->roles[CI_ROLE_GADGET]) {
+		dev_err(dev, "no supported roles\n");
+		ret = -ENODEV;
+		goto rm_wq;
+	}
+
+	if (ci->roles[CI_ROLE_HOST] && ci->roles[CI_ROLE_GADGET]) {
+		ci->is_otg = true;
+		ci->role = ci_otg_role(ci);
+	} else {
+		ci->role = ci->roles[CI_ROLE_HOST]
+			? CI_ROLE_HOST
+			: CI_ROLE_GADGET;
+	}
+
+	ret = ci_role_start(ci, ci->role);
+	if (ret) {
+		dev_err(dev, "can't start %s role\n", ci_role(ci)->name);
 		ret = -ENODEV;
-		goto out;
+		goto rm_wq;
 	}
 
-	platform_set_drvdata(pdev, udc);
-	ret = request_irq(udc->irq, udc_irq, IRQF_SHARED, driver->name, udc);
+	platform_set_drvdata(pdev, ci);
+	ret = request_irq(ci->irq, ci_irq, IRQF_SHARED, ci->udc_driver->name,
+			  ci);
+	if (ret)
+		goto stop;
 
-out:
+	ret = device_create_file(dev, &dev_attr_role);
 	if (ret)
-		udc_remove(udc);
+		goto rm_attr;
+
+	if (ci->is_otg)
+		hw_write(ci, OP_OTGSC, OTGSC_IDIE, OTGSC_IDIE);
+
+	return ret;
+
+rm_attr:
+	device_remove_file(dev, &dev_attr_role);
+stop:
+	ci_role_stop(ci);
+rm_wq:
+	flush_workqueue(ci->wq);
+	destroy_workqueue(ci->wq);
 
 	return ret;
 }
 
-static int __devexit ci_udc_remove(struct platform_device *pdev)
+static int __devexit ci_hdrc_remove(struct platform_device *pdev)
 {
-	struct ci13xxx *udc = platform_get_drvdata(pdev);
+	struct ci13xxx *ci = platform_get_drvdata(pdev);
 
-	free_irq(udc->irq, udc);
-	udc_remove(udc);
+	flush_workqueue(ci->wq);
+	destroy_workqueue(ci->wq);
+	device_remove_file(ci->dev, &dev_attr_role);
+	free_irq(ci->irq, ci);
+	ci_role_stop(ci);
 
 	return 0;
 }
 
-static struct platform_driver ci_udc_driver = {
-	.probe	= ci_udc_probe,
-	.remove	= __devexit_p(ci_udc_remove),
+static struct platform_driver ci_hdrc_driver = {
+	.probe	= ci_hdrc_probe,
+	.remove	= __devexit_p(ci_hdrc_remove),
 	.driver	= {
-		.name	= "ci_udc",
+		.name	= "ci_hdrc",
 	},
 };
 
-module_platform_driver(ci_udc_driver);
+module_platform_driver(ci_hdrc_driver);
 
-MODULE_ALIAS("platform:ci_udc");
+MODULE_ALIAS("platform:ci_hdrc");
 MODULE_ALIAS("platform:ci13xxx");
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("David Lopo <dlopo@chipidea.mips.com>");
-MODULE_DESCRIPTION("ChipIdea UDC Driver");
+MODULE_DESCRIPTION("ChipIdea HDRC Driver");

drivers/usb/chipidea/udc.c

@@ -1592,14 +1592,13 @@ static int ci13xxx_stop(struct usb_gadget *gadget,
  * BUS block
  *****************************************************************************/
 /**
- * udc_irq: global interrupt handler
+ * udc_irq: udc interrupt handler
  *
  * This function returns IRQ_HANDLED if the IRQ has been handled
  * It locks access to registers
  */
-irqreturn_t udc_irq(int irq, void *data)
+static irqreturn_t udc_irq(struct ci13xxx *udc)
 {
-	struct ci13xxx *udc = data;
 	irqreturn_t retval;
 	u32 intr;
 
@@ -1666,38 +1665,24 @@ static void udc_release(struct device *dev)
 }
 
 /**
- * udc_probe: parent probe must call this to initialize UDC
- * @dev:  parent device
- * @regs: registers base address
- * @name: driver name
- *
- * This function returns an error code
- * No interrupts active, the IRQ has not been requested yet
- * Kernel assumes 32-bit DMA operations by default, no need to dma_set_mask
+ * udc_start: initialize gadget role
+ * @udc: chipidea controller
  */
-int udc_probe(struct ci13xxx_udc_driver *driver, struct device *dev,
-	      void __iomem *regs, struct ci13xxx **_udc)
+static int udc_start(struct ci13xxx *udc)
 {
-	struct ci13xxx *udc;
+	struct device *dev = udc->dev;
 	int retval = 0;
 
-	if (dev == NULL || regs == NULL || driver == NULL ||
-			driver->name == NULL)
+	if (!udc)
 		return -EINVAL;
 
-	udc = kzalloc(sizeof(struct ci13xxx), GFP_KERNEL);
-	if (udc == NULL)
-		return -ENOMEM;
-
 	spin_lock_init(&udc->lock);
-	udc->regs = regs;
-	udc->udc_driver = driver;
 
 	udc->gadget.ops          = &usb_gadget_ops;
 	udc->gadget.speed        = USB_SPEED_UNKNOWN;
 	udc->gadget.max_speed    = USB_SPEED_HIGH;
 	udc->gadget.is_otg       = 0;
-	udc->gadget.name         = driver->name;
+	udc->gadget.name         = udc->udc_driver->name;
 
 	INIT_LIST_HEAD(&udc->gadget.ep_list);
 
@@ -1707,16 +1692,12 @@ int udc_probe(struct ci13xxx_udc_driver *driver, struct device *dev,
 	udc->gadget.dev.parent   = dev;
 	udc->gadget.dev.release  = udc_release;
 
-	udc->dev = dev;
-
 	/* alloc resources */
 	udc->qh_pool = dma_pool_create("ci13xxx_qh", dev,
 				       sizeof(struct ci13xxx_qh),
 				       64, CI13XXX_PAGE_SIZE);
-	if (udc->qh_pool == NULL) {
-		retval = -ENOMEM;
-		goto free_udc;
-	}
+	if (udc->qh_pool == NULL)
+		return -ENOMEM;
 
 	udc->td_pool = dma_pool_create("ci13xxx_td", dev,
 				       sizeof(struct ci13xxx_td),
@@ -1726,10 +1707,6 @@ int udc_probe(struct ci13xxx_udc_driver *driver, struct device *dev,
 		goto free_qh_pool;
 	}
 
-	retval = hw_device_init(udc, regs, driver->capoffset);
-	if (retval < 0)
-		goto free_pools;
-
 	retval = init_eps(udc);
 	if (retval)
 		goto free_pools;
@@ -1775,7 +1752,6 @@ int udc_probe(struct ci13xxx_udc_driver *driver, struct device *dev,
 	pm_runtime_no_callbacks(&udc->gadget.dev);
 	pm_runtime_enable(&udc->gadget.dev);
 
-	*_udc = udc;
 	return retval;
 
 remove_trans:
@@ -1796,9 +1772,6 @@ int udc_probe(struct ci13xxx_udc_driver *driver, struct device *dev,
 	dma_pool_destroy(udc->td_pool);
 free_qh_pool:
 	dma_pool_destroy(udc->qh_pool);
-free_udc:
-	kfree(udc);
-	*_udc = NULL;
 	return retval;
 }
 
@@ -1807,7 +1780,7 @@ int udc_probe(struct ci13xxx_udc_driver *driver, struct device *dev,
  *
  * No interrupts active, the IRQ has been released
  */
-void udc_remove(struct ci13xxx *udc)
+static void udc_stop(struct ci13xxx *udc)
 {
 	int i;
 
@@ -1826,12 +1799,37 @@ void udc_remove(struct ci13xxx *udc)
 	dma_pool_destroy(udc->qh_pool);
 
 	if (udc->transceiver) {
-		otg_set_peripheral(udc->transceiver->otg, &udc->gadget);
+		otg_set_peripheral(udc->transceiver->otg, NULL);
 		usb_put_transceiver(udc->transceiver);
 	}
 	dbg_remove_files(&udc->gadget.dev);
 	device_unregister(&udc->gadget.dev);
+	/* my kobject is dynamic, I swear! */
+	memset(&udc->gadget, 0, sizeof(udc->gadget));
+}
+
+/**
+ * ci_hdrc_gadget_init - initialize device related bits
+ * ci: the controller
+ *
+ * This function enables the gadget role, if the device is "device capable".
+ */
+int ci_hdrc_gadget_init(struct ci13xxx *ci)
+{
+	struct ci_role_driver *rdrv;
+
+	if (!hw_read(ci, CAP_DCCPARAMS, DCCPARAMS_DC))
+		return -ENXIO;
+
+	rdrv = devm_kzalloc(ci->dev, sizeof(struct ci_role_driver), GFP_KERNEL);
+	if (!rdrv)
+		return -ENOMEM;
+
+	rdrv->start	= udc_start;
+	rdrv->stop	= udc_stop;
+	rdrv->irq	= udc_irq;
+	rdrv->name	= "gadget";
+	ci->roles[CI_ROLE_GADGET] = rdrv;
 
-	kfree(udc->hw_bank.regmap);
-	kfree(udc);
+	return 0;
 }

drivers/usb/chipidea/udc.h

@@ -71,26 +71,16 @@ struct ci13xxx_req {
 };
 
 #ifdef CONFIG_USB_CHIPIDEA_UDC
-irqreturn_t udc_irq(int irq, void *data);
-int udc_probe(struct ci13xxx_udc_driver *driver, struct device *dev,
-	      void __iomem *regs, struct ci13xxx **_udc);
-void udc_remove(struct ci13xxx *udc);
+
+int ci_hdrc_gadget_init(struct ci13xxx *ci);
+
 #else
-static inline irqreturn_t udc_irq(int irq, void *data)
-{
-	return IRQ_NONE;
-}
 
-static inline
-int udc_probe(struct ci13xxx_udc_driver *driver, struct device *dev,
-	      void __iomem *regs, struct ci13xxx **_udc)
+static inline int ci_hdrc_gadget_init(struct ci13xxx *ci)
 {
-	return -ENODEV;
+	return -ENXIO;
 }
 
-static inline void udc_remove(struct ci13xxx *udc)
-{
-}
 #endif
 
 #endif /* __DRIVERS_USB_CHIPIDEA_UDC_H */